Method and apparatus for establishing a priority call in a fixed wireless access communication system

ABSTRACT

A wireless communication system has a plurality of subscriber stations linked by radio with a network infrastructure coupled to a correspondent node. A call is originated at a subscriber station apparatus. The apparatus includes a call establishment message generator coupled to receive an origination indication of the call. The call establishment message generator generates a call establishment message to initiate call set-up procedures that precurse a request to establish the call between the subscriber station and the correspondent node. The apparatus also includes a response detector coupled to receive an indication of a network-infrastructure generated response to the call establishment message. The response detector detects whether the response to the call establishment message indicates that communication resources are available to establish the call. The apparatus further includes a call set-up emulator coupled to the response detector. The call set-up emulator emulates normal call set-up operations at the subscriber station at least for a period responsive to detection by the response detector of unavailability of the communication resources to establish the priority call.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of and claims priority to copending U.S. patent application Ser. No. 09/839,499 filed on Apr. 20, 2001 and entitled “APPARATUS, AND AN ASSOCIATED METHOD, FOR PROVIDING WLAN SERVICE IN A FIXED WIRELESS ACCESS COMMUNICATION SYSTEM”. The present application may share common subject matter and figures with the above United States patent application, which is incorporated herein by reference for all purposes as if fully set forth herein

This application claims priority to: provisional U.S. Patent Application Ser. No. 60/262,712 filed on Jan. 19, 2001 and entitled “WIRELESS COMMUNICATION SYSTEM USING BLOCK FILTERING AND FAST EQUALIZATION DEMODULATION AND METHOD OF OPERATION”; provisional U.S. Patent Application Ser. No. 60/262,825 filed on Jan. 19, 2001 and entitled “APPARATUS AND ASSOCIATED METHOD FOR OPERATING UPON DATA SIGNALS RECEIVED AT A RECEIVING STATION OF A FIXED WIRELESS ACCESS COMMUNICATION SYSTEM”; provisional U.S. Patent Application Ser. No. 60/262,698 filed on Jan. 19, 2001 and entitled “APPARATUS AND METHOD FOR OPERATING A SUBSCRIBER INTERFACE IN A FIXED WIRELESS SYSTEM”; provisional U.S. Patent Application Ser. No. 60/262,827 filed on Jan. 19, 2001 entitled “APPARATUS AND METHOD FOR CREATING SIGNAL AND PROFILES AT A RECEIVING STATION”; provisional U.S. Patent Application Ser. No. 60/262,826 filed on Jan. 19, 2001 and entitled “SYSTEM AND METHOD FOR INTERFACE BETWEEN A SUBSCRIBER MODEM AND SUBSCRIBER PREMISES INTERFACES”; provisional U.S. Patent Application Ser. No. 60/262,951 filed on Jan. 19, 2001 entitled “BACKPLANE ARCHITECTURE FOR USE IN WIRELESS AND WIRELINE ACCESS SYSTEMS”; provisional U.S. Patent Application Ser. No. 60/262,824 filed on Jan. 19, 2001 entitled “SYSTEM AND METHOD FOR ON LINE INSERTION OF LINE REPLACEABLE UNITS IN WIRELESS AND WIRELINE ACCESS SYSTEMS”; provisional U.S. Patent Application Ser. No. 60/263,101 filed on Jan. 19, 2001 entitled “SYSTEM FOR COORDINATION OF TDD TRANSMISSION BURSTS WITHIN AND BETWEEN CELLS IN A WIRELESS ACCESS SYSTEM AND METHOD OF OPERATION”; provisional U.S. Patent Application Ser. No. 60/263,097 filed on Jan. 19, 2001 and entitled “REDUNDANT TELECOMMUNICATION SYSTEM USING MEMORY EQUALIZATION APPARATUS AND METHOD OF OPERATION”; provisional U.S. Patent Application Ser. No. 60/273,579 filed Mar. 5, 2001 and entitled “WIRELESS ACCESS SYSTEM FOR ALLOCATING AND SYNCHRONIZING UPLINK AND DOWNLINK OF TDD FRAMES AND METHOD OF OPERATION”; provisional U.S. Patent Application Ser. No. 60/262,955 filed Jan. 19, 2001 and entitled “TDD FDD AIR INTERFACE”; provisional U.S. Patent Application Ser. No. 60/262,708 filed on Jan. 19, 2001 and entitled “APPARATUS, AND AN ASSOCIATED METHOD, FOR PROVIDING WLAN SERVICE IN A FIXED WIRELESS ACCESS COMMUNICATION SYSTEM”; Ser. No. 60/273,689, filed Mar. 5, 2001, entitled “WIRELESS ACCESS SYSTEM USING MULTIPLE MODULATION FORMATS IN TDD FRAMES AND METHOD OF OPERATION”; provisional U.S. Patent Application Ser. No. 60/273,757 filed Mar. 5, 2001 and entitled “WIRELESS ACCESS SYSTEM AND ASSOCIATED METHOD USING MULTIPLE MODULATION FORMATS IN TDD FRAMES ACCORDING TO SUBSCRIBER SERVICE TYPE”; provisional U.S. Patent Application Ser. No. 60/270,378 filed Feb. 21, 2001 and entitled “APPARATUS FOR ESTABLISHING A PRIORITY CALL IN A FIXED WIRELESS ACCESS COMMUNICATION SYSTEM”; provisional U.S. Patent Application Ser. No. 60/270,385 filed Feb. 21, 2001 and entitled “APPARATUS FOR REALLOCATING COMMUNICATION RESOURCES TO ESTABLISH A PRIORITY CALL IN A FIXED WIRELESS ACCESS COMMUNICATION SYSTEM”; and provisional U.S. Patent Application Ser. No. 60/270,430 filed Feb. 21, 2001 and entitled “METHOD FOR ESTABLISHING A PRIORITY CALL IN A FIXED WIRELESS ACCESS COMMUNICATION SYSTEM. The above Provisional U.S. Patent Applications are incorporated herein by reference for all purposes as if fully set forth herein.

The present application may share common subject matter and figures with the following United States patent applications, which are incorporated herein by reference for all purposes as if fully set forth herein:

-   1) Copending Ser. No. 10/042,705, filed on Nov. 15, 2000, entitled     “SUBSCRIBER INTEGRATED ACCESS DEVICE FOR USE IN WIRELESS AND     WIRELINE ACCESS SYSTEMS”; -   2) Ser. No. 09/838,810, filed Apr. 20, 2001, entitled “WIRELESS     COMMUNICATION SYSTEM USING BLOCK FILTERING AND FAST     EQUALIZATION-DEMODULATION AND METHOD OF OPERATION”, now U.S. Pat.     No. 7,075,967; -   3) Ser. No. 09/839,726, filed Apr. 20, 2001, entitled “APPARATUS AND     ASSOCIATED METHOD FOR OPERATING UPON DATA SIGNALS RECEIVED AT A     RECEIVING STATION OF A FIXED WIRELESS ACCESS COMMUNICATION SYSTEM”,     now U.S. Pat. No. 7,099,383; -   4) Copending Ser. No. 09/839,729, filed Apr. 20, 2001, entitled     “APPARATUS AND METHOD FOR OPERATING A SUBSCRIBER INTERFACE IN A     FIXED WIRELESS SYSTEM”; -   5) Ser. No. 09/839,719, filed Apr. 20, 2001, entitled “APPARATUS AND     METHOD FOR CREATING SIGNAL AND PROFILES AT A RECEIVING STATION”, now     U.S. Pat. No. 6,947,477; -   6) Ser. No. 09/838,910, filed Apr. 20, 2001, entitled “SYSTEM AND     METHOD FOR INTERFACE BETWEEN A SUBSCRIBER MODEM AND SUBSCRIBER     PREMISES INTERFACES”, now U.S. Pat. No. 6,564,051; -   7) Copending Ser. No. 09/839,509, filed Apr. 20, 2001, entitled     “BACKPLANE ARCHITECTURE FOR USE IN WIRELESS AND WIRELINE ACCESS     SYSTEMS”; -   8) Ser. No. 09/839,514, filed Apr. 20, 2001, entitled “SYSTEM AND     METHOD FOR ON-LINE INSERTION OF LINE REPLACEABLE UNITS IN WIRELESS     AND WIRELINE ACCESS SYSTEMS”, now U.S. Pat. No. 7,069,047; -   9) Ser. No. 09/839,512, filed Apr. 20, 2001, entitled “SYSTEM FOR     COORDINATION OF TDD TRANSMISSION BURSTS WITHIN AND BETWEEN CELLS IN     A WIRELESS ACCESS SYSTEM AND METHOD OF OPERATION”, now U.S. Pat. No.     6,804,527; -   10) Ser. No. 09/839,259, filed Apr. 20, 2001, entitled “REDUNDANT     TELECOMMUNICATION SYSTEM USING MEMORY EQUALIZATION APPARATUS AND     METHOD OF OPERATION”, now U.S. Pat. No. 7,065,098; -   11) Ser. No. 09/839,457, filed Apr. 20, 2001, entitled “WIRELESS     ACCESS SYSTEM FOR ALLOCATING AND SYNCHRONIZING UPLINK AND DOWNLINK     OF TDD FRAMES AND METHOD OF OPERATION”, now U.S. Pat. No. 7,002,929; -   12) Ser. No. 09/839,075, filed Apr. 20, 2001, entitled “TDD FDD AIR     INTERFACE”, now U.S. Pat. No. 6,859,655; -   13) Ser. No. 09/839,458, filed Apr. 20, 2001, entitled “WIRELESS     ACCESS SYSTEM USING MULTIPLE MODULATION FORMATS IN TDD FRAMES AND     METHOD OF OPERATION”, now U.S. Pat. No. 7,173,916. -   14) Ser. No. 09/839,456, filed Apr. 20, 2001, entitled “WIRELESS     ACCESS SYSTEM AND ASSOCIATED METHOD USING MULTIPLE MODULATION     FORMATS IN TDD FRAMES ACCORDING TO SUBSCRIBER SERVICE TYPE”, now     U.S. Pat. No. 6,891,810; -   15) Copending Ser. No. 09/838,924, filed Apr. 20, 2001, entitled     “APPARATUS FOR ESTABLISHING A PRIORITY CALL IN A FIXED WIRELESS     ACCESS COMMUNICATION SYSTEM”; -   16) Ser. No. 09/839,727 filed Apr. 20, 2001 and entitled “APPARATUS     FOR REALLOCATING COMMUNICATION RESOURCES TO ESTABLISH A PRIORITY     CALL IN A FIXED WIRELESS ACCESS COMMUNICATION SYSTEM”, now U.S. Pat.     No. 7,031,738; -   17) Ser. No. 09/839,734, filed Apr. 20, 2001, entitled “METHOD FOR     ESTABLISHING A PRIORITY CALL IN A FIXED WIRELESS ACCESS     COMMUNICATION SYSTEM”, now U.S. Pat. No. 7,035,241; -   18) Ser. No. 09/839,513, filed Apr. 20, 2001, entitled “SYSTEM AND     METHOD FOR PROVIDING AN IMPROVED COMMON CONTROL BUS FOR USE IN     ON-LINE INSERTION OF LINE REPLACEABLE UNITS IN WIRELESS AND WIRELINE     ACCESS SYSTEMS”, now U.S. Pat. Nos. 6,925,516; and -   19) Ser. No. 09/948,059, filed Sep. 5, 2001, entitled “WIRELESS     ACCESS SYSTEM USING SELECTIVELY ADAPTABLE BEAM FORMING IN TDD FRAMES     AND METHOD OF OPERATION”, now U.S. Pat. No. 7,230,931.

The above provisional and non-provisional applications are commonly assigned to the assignee of the present invention.

TECHNICAL FIELD

The present disclosure is directed, in general, to communication network access systems and, more specifically, to memory equalization techniques to establish the call for use in redundant telecommunication equipment and to establish the priority of calls, such as calls requesting emergency assistance or when communication resources are not initially available.

BACKGROUND

Telecommunications access systems provide for voice, data, and multimedia transport and control between the central office (CO) of the telecommunications service provider and the subscriber (customer) premises. Prior to the mid-1970s, the subscriber was provided phone lines (e.g., voice frequency (VF) pairs) directly from the Class 5 switching equipment located in the central office of the telephone company. In the late 1970s, digital loop carrier (DLC) equipment was added to the telecommunications access architecture. The DLC equipment provided an analog phone interface, voice CODEC, digital data multiplexing, transmission interface, and control and alarm remotely from the central office to cabinets located within business and residential locations for approximately 100 to 2000 phone line interfaces. This distributed access architecture greatly reduced line lengths to the subscriber and resulted in significant savings in both wire installation and maintenance. The reduced line lengths also improved communication performance on the line provided to the subscriber.

By the late 1980s, the limitations of data modem connections over voice frequency (VF) pairs were becoming obvious to both subscribers and telecommunications service providers. ISDN (Integrated Services Digital Network) was introduced to provide universal 128 kbps service in the access network. The subscriber interface is based on 64 kbps digitization of the VF pair for digital multiplexing into high speed digital transmission streams (e.g., T1/T3 lines in North America, E1/E3 lines in Europe). ISDN was a logical extension of the digital network that had evolved throughout the 1980s. The rollout of ISDN in Europe was highly successful. However, the rollout in the United States was not successful, due in part to artificially high tariff costs which greatly inhibited the acceptance of ISDN.

More recently, the explosion of the Internet and deregulation of the telecommunications industry have brought about a broadband revolution. To meet increased demands for both voice and data services at greatly reduced costs, high speed DSL (digital subscriber line) modems and cable modems have been developed and introduced. Additionally, the DLC architecture was extended to provide remote distributed deployment at the neighborhood cabinet level using DSL access multiplexer (DSLAM) equipment. Thus, the increased data rates provided to the subscriber resulted in the upgrade of DLC/DSLAM transmission interfaces from T1/E1 interfaces (1.5/2.0 Mbps) to high speed DS3 and OC3 interfaces. In a similar fashion, the entire telecommunications network backbone has undergone and is undergoing continuous upgrade to wideband optical transmission and switching equipment.

Similarly, wireless access systems have been developed and deployed to provide broadband access to both commercial and residential subscriber premises. Initially, the market for wireless access systems was driven by rural radiotelephony deployed solely to meet the universal service requirements imposed by government (i.e., the local telephone company is required to serve all subscribers regardless of the cost to install service). The cost of providing a wired connection to a small percentage of rural subscribers was high enough to justify the development and expense of small-capacity wireless local loop (WLL) systems.

Deregulation of the local telephone market in the United States (e.g., Telecommunications Act of 1996) and in other countries shifted the focus of fixed wireless access (FWA) systems deployment from rural access to competitive local access in more urbanized areas. In addition, the age and inaccessibility of much of the older wired telephone infrastructure make FWA systems a cost-effective alternative to installing new, wired infrastructure. Also, it is more economically feasible to install FWA systems in developing countries where the market penetration is limited (i.e., the number and density of users who can afford to pay for services is limited to small percent of the population) and the rollout of wired infrastructure cannot be performed profitably. In either case, broad acceptance of FWA systems requires that the voice and data quality of FWA systems must meet or exceed the performance of wired infrastructure.

Wireless access systems must address a number of unique operational and technical issues including:

1) Relatively high bit error rates (BER) compared to wire line or optical systems; and

2) Transparent operation with network protocols and protocol time constraints for the following protocols:

-   -   a) ATM;     -   b) Class 5 switch interfaces (domestic GR-303 and international         V5.2);     -   c) TCP/IP with quality-of-service QoS for voice over IP (VoIP)         (i.e., RTP) and other H.323 media services;     -   d) Distribution of synchronization of network time out to the         subscribers;

3) Increased use of voice, video and/or media compression and concentration of active traffic over the air interface to conserve bandwidth;

4) Switching and routing within the access system to distribute signals from the central office to multiple remote cell sites containing multiple cell sectors and one or more frequencies of operation per sector; and

5) Remote support and debugging of the subscriber equipment, including remote software upgrade and provisioning.

Unlike physical optical or wire systems that operate at bit error rates (BER) of 10⁻¹¹, wireless access systems have time varying channels that typically provide bit error rates of 10⁻³ to 10⁻⁶. The wireless physical (PHY) layer interface and the media access control (MAC) layer interface must provide modulation, error correction and ARQ protocol that can detect and, where required, correct or retransmit corrupted data so that the interfaces at the network and at the subscriber site operate at wire line bit error rates.

Wireless access systems should also sustain high availability for users. A necessary part of achieving high availability telecommunications systems, such as wireless access systems, is design of critical components in a redundant fashion where an “active” side handles primary functionality while a “standby” side remains idle but quickly available in the event of failure within the primary side. Being redundant, both resources are necessarily capable of performing the same system functions.

For systems which are processor controlled, the active side typically maintains status and control information for all resources which the active side controls within a private memory. Upon failure of the active side, the standby side must begin operation within a minimal amount of time. During switch-over from the active side to the standby side for primary functionality, a primary concern is that no change is apparent (transparency) to the end user. To accomplish such transparency to the end user, the standby side is generally abreast with any and all changes on the primary side (equalization) as closely as possible in real time. As a result of equalization, the standby side is able to quickly begin processing with a duplicate copy of the status and control information which the active side was utilizing at the time of failure within the active side.

Two techniques are typically employed in order to achieve equalization of active and standby memory contents: software-based and hardware-based. With software-based techniques, the processor on the active side copies certain critical information, formats the copied information into a message form and transmits the message to the standby side processor, all under software control. The control processor on the standby side receives the message and interprets the content to determine whether the message contains equalization information to be moved appropriately into the private memory of the standby side control processor, again all under software control. However, the amount of time required to format and transfer data utilizing, the need for a messaging protocol and verification of data integrity, and the need to interpret and properly store data on the standby side all increase the overhead associated with this method. Additionally, these requirements all add to the latency (delay) associated with keeping the two sides equalized.

Latency in memory equalization has two principal effects: First, the speed at which the active side processes calls is reduced since the active side is unable to process calls faster than the rate at which associated information is transferred to the standby side and properly stored. If the active side processes calls faster than the transfer rate to the standby side, the standby side falls behind in maintaining an accurate copy of the active side's status and control information (coherency), which defeats the purpose of equalization. Second, as latency in memory equalization increases, so does the probability of data loss for data essential to resuming operations in the standby side in the event of failure in the active side. Furthermore, attempts to speed transfers between the active and standby sides to reduce latency generally require dedicating more processing time to memory equalization-related tasks, which inherently reduces the amount of processing time available for non-redundancy tasks (e.g., call processing).

With hardware-based techniques for active and standby memory equalization, the active and standby components are typically very tightly coupled—in some instances to the extent that both processors are synchronized for every instruction. Since both sides operate on exactly the same instruction at exactly the same time, both sides are kept equalized. However, this technique requires considerable expense to implement and, although guarding against hardware failures, suffers the side effect of vulnerability to software failures. For example, a logic flaw on the active side will be exactly duplicated on the standby side, corrupting potentially mission-critical data even as both sides are kept equalized.

Fixed wireless broadband systems use a group of transceiver base stations to cover a region in the same manner as the base stations of a cellular phone system. The base stations of a fixed wireless broadband system transmit forward channel (i.e., downstream) signals in directed beams to fixed location antennas attached to the residences or offices of subscribers. The base stations also receive reverse channel (i.e., upstream) signals transmitted by the broadband access equipment of the subscriber.

Unfortunately, the diversity of broadband access technology has resulted in a lack of standardization in the broadband access equipment. Cable modems and DSL routers are incompatible with each other and with fiber optic equipment. Different service providers locate broadband access equipment in different locations on the subscriber premises. Often this equipment is located inside the office or residence of the subscriber, which makes it inaccessible to maintenance workers unless the subscriber is present to admit the workers to the premises. The lack of standardization of broadband access equipment and the frequent inaccessibility of such equipment adds to the cost and complexity of broadband access.

Concentration techniques are utilized in construction of many multi-user communication systems. Concentration techniques, generally, refer to selection of the number of users permitted to be part of the system to be greater, by some factor, than the actual capacity of the communication system. Statistical, or other, analysis is made of the likely number of users of the communication system at any particular time, and the system is constructed to support a number of users based upon the expected number of users.

During times in which actual usage of the communication exceeds the capacity of the system, additional users, beyond the system's capacity, are prevented, or blocked, from access to the system. When the communication system comprises a conventional wireline, telephonic communication system, the additional users are provided indication of their failure to access the system by alerting such users with audible alerts. The audible alerts are audibly distinct from normal dial tones generated during normal telephonic operation.

In a fixed wireless access communication system, capacity limitations are possible between both the network infrastructure of the system and a correspondent node forming a terminating or originating station as well as, additionally, the radio links extending between the network infrastructure and the subscriber stations.

When, for instance, a user at the subscriber station needs to place a priority call, such as a request for emergency assistance to an emergency dispatch center, access to the communication system to communicate with the emergency dispatch center is essential. A need therefore exists to provide access to a communication system to establish the priority call with the emergency dispatch center. It would also be desirable to provide a manner by which to operate the communication system in which the user is not made aware of an initial blockage from access to the system if access shall subsequently be granted.

Therefore, there is a need in the art to increase the communication capacity of the communication system regardless of whether it is a fixed wireless system. There is also a need in the art for a memory equalization technique which reduces equalization latency over software-based equalization methods while avoiding the expense and software error vulnerability of hardware-based equalization methods while addressing call priority issues.

SUMMARY

To address the above-discussed deficiencies of the prior art, it is a primary object of the present disclosure to provide a system to initiate establishment of a priority call, such as a call to request emergency assistance, in a wireless communication system.

A wireless communication system has a plurality of subscriber stations that are operable to communicate by way of radio links with a network infrastructure to which a correspondent node is coupled. A call is originated at an apparatus in one of the subscriber stations. The apparatus includes a call establishment message generator that is coupled to receive an indication of the initiation of the origination of the call at the subscriber station. The call establishment message generator is operable to generate a call establishment message for communication to the network infrastructure to initiate call set-up procedures that precurse a request to establish the call between the subscriber station and the correspondent node. The apparatus also includes a response detector that is coupled to receive an indication of a network-infrastructure generated response to the call establishment message. The response detector is operable to detect whether the response to the call establishment message indicates that communication resources are available to establish the call. The apparatus further includes a call set-up emulator that is coupled to the response detector. The call set-up emulator is operable to emulate normal call set-up operations at the subscriber station at least for a period responsive to detection by the response detector of unavailability of the communication resources to establish the priority call.

The foregoing has outlined rather broadly the features and technical advantages of the present disclosure so that those skilled in the art may better understand the detailed description of the disclosure that follows. Additional features and advantages of the disclosure will be described hereinafter that form the subject of the claims of the disclosure. Those skilled in the art should appreciate that they may readily use the conception and the specific embodiment disclosed as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the disclosure in its broadest form.

The present disclosure will be better understood when read in light of the accompanying drawings which are described in the detailed description herein below and in light of the claims appended hereto.

Before undertaking the DETAILED DESCRIPTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, wherein like numbers designate like objects, and in which:

FIG. 1 illustrates a functional block diagram of an exemplary fixed wireless access (FWA) network in which an embodiment of the present disclosure is operable.

FIG. 2 illustrates an exemplary data frame, as defined by the fixed wireless access network in FIG. 1, according to an embodiment of the present disclosure;

FIG. 3 illustrates a functional block diagram of portions of the fixed wireless access communication system shown in FIG. 1; and

FIG. 4 illustrates a message sequence diagram exemplary of signaling generated during operation of the communication system shown in FIGS. 1 and 3 pursuant to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Now, referring to FIG. 1, a communication system, shown generally at 10, provides for communications with the subscriber stations, of which the subscriber station 12 is exemplary, to an emergency dispatch center 34. Communications are effectuated with the subscriber station by way of radio links formed upon an air interface 14. Data originated at an appropriately-positioned subscriber station can be communicated to a correspondent node (e.g., an emergency dispatch center) 16 by way of a communication path by way of the radio links formed upon the air interface. Data originated at the correspondent node 16 can be communicated upon a communication path formed between a correspondent node and a subscriber station. Two-way communication between the subscriber station and the correspondent node is thereby possible.

In the exemplary implementation, the communication system 10 forms a fixed wireless access (FWA) system coupled to a network backbone, of which the combined path data network (PDN) and public-switched telephonic network (PSTN) 18 is representative in the figure.

While the following description of operation of an embodiment of the present disclosure shall describe its operation with respect to the exemplary implementation of the communication system shown in the figure it should be understood that operation of an embodiment of the present disclosure is analogously also operable in other types of communication systems which use concentration techniques or otherwise are susceptible to access limitations. For example, the principles of the present disclosure may be used in those systems that are not considered fixed wireless system such as mobile, portable or battery-powered wireless systems that serve as emergency backups for fixed systems in case of a power blackout or natural disaster.

The fixed wireless access system includes a plurality of base transceiver stations of which the base transceiver/remote modem (BTS/RM) 22 shown in the figure is exemplary. Each base transceiver station defines a cell. Here, the base transceiver station 22 defines a cell 24. The subscriber station 12 is here positioned at a location encompassed by the cell 24. A plurality of other subscriber stations is also positionable at locations encompassed by the cell 24. And, other subscriber stations positioned in other cells defined by other base transceiver stations typically form parts of a fixed wireless access communication system. Similar system attributes are present in mobile, portable or battery-powered wireless systems.

Concentration techniques are used in system construction. That is to say, system construction permits a high ratio of subscriber stations to base transceiver stations such that, if all of the subscriber stations simultaneously attempt to effectuate communication sessions, the communication capacity of the base transceiver stations would be exceeded. Through the use of concentration techniques, a statistical, or other, determination is made of an appropriate number of subscriber stations to be permitted to be associated with a particular base transceiver station. Not all of the subscriber stations are likely to attempt to effectuate simultaneous communication sessions, thereby permitting the number of permitted subscriber stations to be increased.

While any of the large variety of different types of communications are effectuable, of significance to an embodiment of the present disclosure are telephonic communications originated at the subscriber station. A telephonic station 26 is here shown to be located at the subscriber station 12.

Use of the terminology communications by the subscriber station and by the telephonic station shall be used, at times, interchangeably below to indicate communications by the telephonic station with the correspondent node 16. And, while only a telephonic station 26 is shown to be positioned at the subscriber station, other types of communication devices such as computer stations and consumer-electronic devices, can also be represented at the subscriber station.

An integrated access device (IAD) 28 is also shown to be positioned at the subscriber station. The integrated access device (IAD) unit includes transceiver circuitry capable of communicating by way of the air interface with the base transceiver station 22. The telephonic station 26 is coupled to the integrated access device 28 and communications are effectuated with the subscriber station by way of the integrated access device.

The base transceiver station 22 forms a portion of the network infrastructure of the fixed wireless access system. Groups of base transceiver stations are coupled to an access processor (AP) 32. And, in turn, the access process is coupled to the network 18. During operation of an embodiment of the present disclosure, communication resources required to establish a call between the telephonic station 26 and the correspondent node 16 are selectably provided. Communication resources both at the air interface 14 and through the network 18 must be available to establish the call between the telephonic station 26 and the correspondent node 16.

FIG. 2 illustrates portions of the communication system 10 to illustrate operation of an embodiment of the present disclosure. Operation of an embodiment of the present disclosure permits a user of the telephonic station 26 positioned at the subscriber station 12 to originate a call to an emergency dispatch center 34 at which the correspondent node 16 is located. Similarly, a user of a mobile, portable or battery-powered wireless system may use a mobile station, cellular phone or other mobile communication device to originate a call to an emergency dispatch center 34 at which the correspondent node 16 is located.

Elements shown in the figure are functional representations, portions of which are implemented, in exemplary implementation, as algorithms executable at processing devices. Additionally, functional operation of the various elements, or portions thereof, can be distributed at several locations or elements of the communication system. Here, for instance, the transmit and receive circuitry portions 36 and 38 are implemented at the integrated access device 28, at the telephonic station 26, or at other portions of the subscriber stations.

When a call is placed to the emergency dispatch center, a pseudo-universal dialing code, such as a 9-1-1 dialing code is entered at the telephonic station of the subscriber station.

A user interface 42 is also positioned at the subscriber station. The user interface includes, for instance, an actuation key pad located on the telephonic station which permits user actuation thereof to enter dialing digits associated with a terminating station such as the correspondent node 16 at the emergency dispatch center 34. The user interface is also representative of a hook switch associated with the telephonic station upon which a telephonic handset is conventionally positioned, to be removed therefrom when a call is to be initiated.

The user interface is coupled to apparatus 44 of an embodiment of the present disclosure. The apparatus 44 is formed of functional elements implemented, for instance, by algorithms executable by control circuitry.

Here, a call establishment message generator 46 is coupled to the user interface to receive indications of off-hook indications indicated thereat. An off-hook indication is indicated when a telephonic station is taken off the hook switch when a user intends to initiate a call with a terminating station. The call establishment message generator generates a call establishment message when the off-hook indication is provided thereto. The call establishment message is provided to the transmit circuitry 36 to be transmitted to the network infrastructure to inform the network infrastructure of the imminent request for establishment of a call with a terminating station.

The network infrastructure, here formed of both the base transceiver station 22 and access processor 32 is also shown to include both transmit circuitry and receive circuitry portions 52 and 54, respectively. The transmit and receive circuitry portions are implemented, for example, at the base transceiver station 22.

The call establishment message transmitted by the subscriber station to the network infrastructure is detected at the receive circuitry 52. Apparatus of an embodiment of the present disclosure, here referenced at 56 is coupled to the receive and transmit circuitry 52 and 54. Elements forming the apparatus 56 are also functionally represented and can be implemented in any of various manners, including by algorithms executable by control circuitry. The elements forming the apparatus 56 can be distributed at different locations of the network infrastructure or coupled thereto.

When a call establishment message is received at the receive circuitry, detection is made of its reception by a call establishment message detector 58. The call establishment message detector is coupled to a communication resource availability determiner 62. The communication resource availability determiner 62 is operable at least responsive to detection of reception of the call establishment message at the network infrastructure. The communication resource availability determiner 62 is operable to determine the availability of communication resources, both in the network 18 and upon the air interface 14, of communication resources to establish a call of indeterminate priority. Determinations are made, for instance, responsive to indications of other ongoing communication sessions with other subscriber stations as well as ongoing communication sessions making use of the network 18.

Determinations made by the determiner 62 are provided to a response generator 64. The response generator 64 generates a response signal which is provide to the transmit circuitry 54. The response signal is transmitted by way of the air interface 14 to the subscriber station 12. The response serves to acknowledge reception at the network infrastructure of the call establishment message and also to provide an indication to the subscriber station of the availability of communication resources to establish a call originated at the subscriber station.

When the response is received at the receive circuitry 38 of the subscriber station, a response detector 68 detects reception at the subscriber station of the response. If the response indicates that communication resources are unavailable to establish a call, originated at the subscriber station, an indication is provided to a call set-up emulator 72. The call set-up emulator 72 is operable to emulate normal operation of call set-up procedures even though the response indicates the communication resources to be unavailable to establish the call. The call set-up emulator 72 includes, for instance, a dial tone generator which generates a conventional telephonic dial tone audibly detectable by a user of the telephonic station. Here, the oscillator 74 is representative of an oscillating signal used in the generation of a dial tone. The emulator is also coupled to the user interface 42 to receive indications of dialing digits or other actuator inputs input by way of the user interface. For instance when dialing digits are entered, the generated dial tone is terminated and appropriate audibly-detectable tones are generated responsive to the entry of the dialing digits or other input actuations.

Indications of the entered dialing digits are also provided to a dialing digit signal generator 76. The dialing signal generator 76 generates a dialing digit signal which is provided to the transmit circuitry 36 to be transmitted to the network infrastructure.

When the dialing digit signal is received at the receive circuitry, detection of the signal is made by a dialing digit indication detector 82. The detector 82 detects the values of the dialing digits. Detection is at least made as to whether the values of the dialing digits are those corresponding to the emergency dispatch center, or other priority location. When detection is made of dialing digits corresponding to the emergency dispatch center, or other priority location, an indication of such is given to a resource reallocator 84. The resource reallocator 84 is operable to reallocate the allocation of communication resources in the communication system to permit the establishment of the call between the subscriber station and the emergency dispatch center. Resource reallocation caused to be effectuated by the resource reallocator 84 includes, for instance, termination of ongoing communication sessions to make available the communication resources to permit the call to the emergency dispatch center, or other priority location, to be established. Selection of which of the ongoing communication session, or sessions, to be terminated is made, for instance, upon random selection, or based upon subscription service levels to which the different subscriber stations have subscribed.

Thereby, a call is able to be established between the subscriber station and the emergency dispatch center, even when the communication resources are not initially available to permit the establishment of the call. And, through the use of the call set-up emulator at the subscriber station, the originator of the call is not made aware of the initial unavailability of the communication resources.

FIG. 3 shows portions of the fixed wireless network, here shown at 300 of an embodiment of the present disclosure. The fixed wireless network, is here show to include a subscriber integrated access device (SIAD) 304 located at a subscriber premises. The SIAD 304 includes radio circuitry 306 capable of transceiving radio signals and a transceiver base station 308. While FIG. 3 exemplifies portions of a fixed wireless network, it should be understood that operation of the present disclosure is analogously also operable in other communication systems such as mobile, portable or battery-powered wireless systems.

The radio circuitry 306 of the SIAD 304 is here capable of generating both voice and data packets, here represented by the blocks 312 and 314. The voice packets are representative of voice packets generated during operation of a telephony handset which is operable in convention manner but connected to the radio circuitry of the SIAD.

The transceiver base station is coupled to an access processor shelf 322 which here functionally is shown to include a table 324 at which active call information is stored, and a resource allocator 326 which allocates communication resources in the fixed wireless network.

The access processor communicates traffic and signaling information by way of the element 328 on the lines 332 with a network interface 334. The network interface 334 is coupled to the PSTN/IP network 336. The network 336 is, in turn, connected to a communication station, here located at an emergency dispatch center 338.

A telephony handset located at the SIAD 304 can be used, for instance, to phone an emergency request for emergency assistance to personnel at the emergency dispatch center. The call, when established, permits a call originator who places the call to request emergency assistance. Due to the potentially emergency nature of the call, it is essential that the call be established. Due to the use of concentration techniques in system construction, there is a possibility that system capacity would not permit establishment of the call, and the request for emergency assistance at the emergency dispatch center would not be completed. During operation of an embodiment of the present disclosure, a manner is provided by which to better assure that the call is established.

FIG. 4 illustrates a message sequence diagram, shown generally at 400, representative of operation of a fixed wireless network shown in FIG. 3. Signaling is initiated at the SIAD 304 when a telephony handset is taken off-hook. As soon as the telephony handset is taken off-hook, a call establishment message is generated, indicated by the segment 404, and sent to the access processor 322. A determination is made as to whether resources are available to establish a call. In the exemplary scenario, resources are not available to establish a call, and an indication of the unavailability of the resources, indicated by the segment 406, is returned to the SIAD.

Upon receipt of the indication of the unavailability of the resources, normal call set-up procedures are emulated, indicated by the block 408. Emulation procedures include, for instance, generation of a dial tone which is local to the SIAD but otherwise appearing to be normal operation of the telephony handset to a user thereof. The user, upon detecting the dial tone, dials, or otherwise enters, digits associated with the emergency dispatch center, such as the emergency digits 9-1-1 forming a pseudo universal emergency number in the United States. The entered digits of the dialing code are captured, indicated at the block 410, and a digit message is generated and transmitted by the segment 412 to the access processor 322.

At the access processor a determination is made as to whether the values of the digits contain in the digit message are associated with the emergency dispatch center or are otherwise associated with the priority call. If not, a terminate call message indicated by the segment 414 is returned to the SIAD. A terminate call message is identified at the telephony handset at the SIAD as a fast busy signal.

If, conversely, the digit message is of values corresponding to an emergency dispatch center, or is otherwise representative of a priority call, a decision is made to permit the establishment of the call. To free resources to permit the establishment of the call, a non-priority call is terminated, indicated by the block 416. A non priority call is terminated, such as by randomly terminating an active call selected from the table 324, (shown in FIG. 3). A priority might also be associated with the act of calls, and a lowest-priority act of call is first-terminated. Or, a random termination of a lowest-priority call is performed. Thereby, resources are made available to establish the call between the telephony handset and the emergency dispatch center. Thereafter, and as indicated by the segment 418, a message is sent to the PSTN to cause a call to be established therethrough. Normal call operations, indicated by the block 422 is thereafter effectuated at the 911, or other priority call, continues until one side, or the other, of the communication sessions goes on-hook.

Although the present disclosure has been described in detail, those skilled in the art should understand that they can make various changes, substitutions and alterations herein without departing from the spirit and scope of the disclosure in its broadest form. 

1. In a fixed wireless access (FWA) communication system having at least a first fixed-site base station and at least a first fixed-site subscriber station capable of communicating with the first fixed-site base station, an improvement of apparatus for facilitating radio communication with a mobile station, said apparatus comprising: a first local-network radio transceiver positioned at the at least the first fixed-site subscriber station said first local-network radio transceiver for selectably transceiving communication signals with the mobile station upon a first local radio link formed between the first local-network radio transceiver and the mobile station when the mobile station is positioned within a selected range of the first fixed-site subscriber station.
 2. The apparatus of claim 1 wherein the fixed-site subscriber station includes a large-area-network transceiver positioned thereat for transceiving communication signals upon a large-area radio link with the fixed-site base station and wherein said first local-network radio transceiver is coupled to the large-area-network transceiver such that communication signals generated at the fixed-site base station, communicated upon the large-area radio link and received at the large-area-network transceiver, are routed to said first local-area-network transceiver to be communicated to the mobile station upon the local radio link.
 3. The apparatus of claim 2 wherein communication signals generated at the mobile station and communicated upon the local radio link to said first local-network transceiver are routed to the large-area-network transceiver to be communicated upon the large-area radio link to the fixed-sited base station.
 4. The apparatus of claim 2 wherein the large-area-network transceiver comprises a rack assembly having at least one expansion slot at which card-mounted circuitry is connectable, thereafter to form a portion of the rack assembly and wherein said first local-network transceiver comprises a local area network card connectable to the expansion slot.
 5. The apparatus of claim 1 wherein the at least the first fixed-site subscriber station comprises the first fixed-site subscriber station and at least a second fixed-site subscriber station, and wherein said apparatus further comprises: a second local-network transceiver positioned at the second fixed-site subscriber station, said second local-network radio transceiver for selectably transceiving communication signals with the mobile station upon a second local radio link formed between the second local-network radio transceiver and the mobile station when the mobile station is positioned within a selected range of the second fixed-site subscriber station.
 6. The apparatus of claim 5 wherein said first local-network transceiver defines a first cellular area within which the mobile station is capable of transceiving the communication signals with said first local-network transceiver and wherein said second local-network transceiver defines a second cellular area within which the mobile station is capable of transceiving the communication signals with said second local-network transceiver.
 7. The apparatus of claim 6 wherein the first cellular area defined by said first local-network transceiver and the second cellular area defined by said second local-network transceiver at least partially overlap and wherein selection is made of with which one of said first and second local-network transceivers, respectively, that the mobile station communicates responsive to determination of at least one communication parameter.
 8. The apparatus of claim 7 wherein the at least one communication parameter responsive to which selection is made of with which one of said first and second local-network transceiver that the mobile station communicates comprises a signal quality parameter.
 9. The apparatus of claim 7 wherein the at least one communication parameter responsive to which selection is made of with which one of said first and second local-network transceivers that the mobile station communicates comprises a system load-related parameter.
 10. The apparatus of claim 6 wherein the mobile station is permitted movement at least between the first cellular area and the second cellular area and wherein communication hand-offs are performed between said first local-network transceiver and said second local-network transceiver responsive to movement of the mobile station between the first cellular area and the second cellular area defined by said first local-network transceiver and said second local-network transceiver, respectively.
 11. In the fixed wireless access system of claim 10, a further improvement of a routing map coupled to the at least the first fixed-site base station, said routing map containing an indication of in which of the first cellular area and the second cellular area that the mobile station is positioned.
 12. In the fixed wireless access system of claim 11 wherein the at least the first fixed-site base station is connected to an access processor and wherein said routing map is located at the access processor.
 13. The routing map of claim 12 wherein the indication of in which cellular area that the mobile station is located is updated responsive to changes in location of the mobile station.
 14. The routing map of claim 12 wherein routing of communication signals to the mobile station is selected responsive to values of the indication contained thereat.
 15. The routing map of claim 14 wherein, subsequent to updating of the values of the indication contained thereat, and responsive to hand-off of communications between said first local-network radio transceiver and said second local-network radio transceiver, undelivered communication signals are rerouted according to updated values of the indication.
 16. In a method for communicating in a fixed wireless access (FWA) communication system having at least a first fixed-site base station and at least a first fixed-site subscriber station capable of communicating with the first fixed-site base station, an improvement of a method for facilitating radio communications with a mobile station, said method comprising: positioning a first local-network radio transceiver at the at least the first fixed-site subscriber station; and selectably transceiving communication signals with the mobile station when a first local radio link formed between the first local-network radio transceiver and the mobile station when the mobile station is positioned within a selected range of the first fixed-site subscriber station.
 17. The method of claim 16 wherein the first fixed-site subscriber station includes a large-area-network transceiver positioned thereat for transceiving communication signals upon a large-area radio link with the fixed-site base station and wherein said operation of positioning comprises coupling the first local-network radio transceiver to the large-area-network transceiver such that communication signals generated at the fixed-site base station, communicated upon the large-area radio link and received at the large-area-network transceiver, are routed to the first local-area-network transceiver to be communicated to the mobile station upon the local radio link.
 18. The method of claim 16 wherein the at least the fixed-site subscriber station comprises the first fixed-site subscriber station and at least a second fixed-site subscriber station, said method further comprising the operation of positioning a second local-network radio transceiver at the second fixed-site subscriber station.
 19. The method of claim 18 wherein the mobile station moves between coverage areas defined by the first local-network radio transceiver and by the second local-network radio transceiver, said method further comprising the operation of handing-off communications with the mobile station between the first local-network radio transceiver and the second local-network radio transceiver when the mobile station moves between the coverage areas.
 20. The method of claim 19 comprising the additional operation of maintaining a routing map indicting a routing map indicating in which coverage area the mobile station is positioned. 